Name and publication

Phytophthora marrasii Bregant, Rossetto & Linald. (2021)

Bregant C, Rossetto G, Deidda A, Maddau L, Franceschini A, Ionta G, Raiola A, Montecchio L, Linaldeddu BT. 2021. Phylogeny and pathogenicity of Phytophthora species associated with artichoke crown and root rot and description of Phytophthora marrasii sp. nov. Agriculture 9: 873.

Corresponding author: benedetto.linaldeddu@unipd.it

Nomenclature

Mycobank

MB840582

Etymology

in honour and memory of Professor Francesco Marras for his outstanding work on globe artichoke diseases

Typification

Type: ITALY: Samassi, isolated from a globe artichoke root, 17 February 2021, collected by B.T. Linaldeddu, isolated by Carlo Bregant, HOLOTYPE CBS H-24776, a dried culture on CA

Ex-type: culture CBS 148033 = CB150

Sequences for ex-type in original manuscript:  ITS MZ569854, β-tubulin MZ603724, cox1 OK054535

Ex-type in other collections

(ET) CBS 148033, NRRL 64314, CB150 (C. Bregant), S&T BL 216 (Abad)

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of the ex-type (see Molecular protocols page)

Phytophthora marrasii ITS rDNA, COI

Voucher sequences for Molecular Toolbox with seven genes (ITS, β-tub, COI, EF1α, HSP90, L10, and YPT1

(see Molecular protocols page) (In Progress)

Voucher sequences for Metabarcoding High-throughput Sequencing (HTS) Technologies [Molecular Operational Taxonomic Unit (MOTU)]

(see Molecular protocols page) (In Progress)

Sequences with multiple genes for ex-type in other sources

• NCBI: Phytophthora marrasii
• EPPO-Q-bank: Phytophthora marrasii
• BOLDSYSTEMS: Phytophthora marrasii

Position in multigenic phylogeny with 7 genes (ITS, β-tub, COI, EF1α, HSP90, L10, and YPT1)

Clade clade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
8e

Morphological identification

Colonies and cardinal temperatures

Colony colony:
assemblage of hyphae which usually develops form a single source and grows in a coordinated way
morphology cottony on PDA, stellate on MEA, and rosaceous to stellate on CA. Minimum growth temperature <2°C, optimum 13°C, and maximum 28°C.

Conditions for growth and sporulation

SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
produced on pond water with Quercus suber roots after 36-72 hours. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are formed abundantly in single culture when flooded with pond water.

Asexual phase

SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
were non-papillate, persistentpersistent:
pertaining to sporangia that remain attached to the sporangiophore and do not separate or detach easily (cf. caducous)
, and predominantly ovoidovoid:
egg-shaped, with the widest part at the base of the sporangium and the narrow part at the apex
to ellipsoidellipsoid:
refers to a solid body that forms an ellipse in the longitudinal plane and a circle in cross section; many fungal spores are ellipsoidal or elliptic
in shape with external and internal proliferationinternal proliferation:
internal proliferation occurs when the sporangiophore continues to grow through an empty sporangium
, both nested and extended. SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
averaged 74 x 31 µm (overall range 48–132 x 21.6–41.6 µm); Sporangiophores simple. Hyphal swellings present. ChlamydosporesChlamydospores:
an asexual spore with a thickened inner wall&nbsp;that is delimited from the mycelium by a septum; may be terminal or intercalary, and survives for long periods in soil
present.

Sexual phase

Homothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
smooth-walled, average size 30.7 µm. OosporesOospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
apleroticaplerotic:
pertaining to a mature oospore that does not fill the oogonium; i.e. there is room left between the oospore wall and oogonium wall (cf. plerotic)
, average size 28.4 µm. AntheridiaAntheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
amphigynousamphigynous:
pertaining to the sexual stage in which the antheridium completely surrounds the stalk of the oogonium (cf. paragynous)
.

Most typical characters

In multiple gene phylogenies P. marrasii is placed within cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
8, but it does not cluster with any of the currently defined clades. Rather, it is basal to Clades 8b and 8d.

Additional specimen(s) evaluated

ITALY: Samassi, isolated from rhizosphere and fine roots of a globe artichoke plant, 17 February 2021, collected by B.T. Linaldeddu, isolated by Carlo Bregant; CB149

Hosts and distribution

Distribution: Italy
Substrate: root and crown rot
Disease note: represented by stunted growth, wilting and necrosis of basal leaves, dark brown discoloration of stem tissues, and crown and root rot
Host: Cynara cardunculus var. scolymus (globe artichoke)

Additional references and links

• SMML USDA-ARS: Phytophthora marrasii
• EPPO Global Database: Phytophthora marrasii
• Forest Phytophthoras of the world: Phytophthora marrasii
• CABI Digital Library: Phytophthora marrasii
• Encyclopedia of Life (EOL): Phytophthora marrasii
• Index Fungorum (IF): Phytophthora marrasii

Fact sheet author

Treena Burgess, Ph.D., Phytophthora Science and Management, Harry Butler Institute, Murdoch University, Australia

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Plant Pathogen Confirmatory Diagnostics Laboratory (PPCDL), United States of America.